MSRA-2301

MSRA-2301

A 23-year-old man is sent to your office for evaluation by his family. The patient recently graduated from university and has had trouble adapting and fitting in. His parents note that he has always been a loner, preferring to stay in his room. They hoped graduation would bring him out of his shell. He has not made any new friends, but only his parents are bothered by this. Instead of socialising, he seems to have continued to stay alone in his room.
On interview, he is withdrawn and quiet. His range of affect is restricted, and he displays no clear happiness or joy when discussing activities that he reports enjoying. He denies any auditory or visual hallucinations and has no suicidal or homicidal intent. He reports that he has no change in his sleep, appetite, energy or concentration.
What is the most likely diagnosis in this patient?